Printing telegraph system



May 24, 1949. J. B. MOORE 2,471,076

PRINTING TELEGRAPH SYSTEM IN V EN TOR.

May 24, 1949. J. B. MOORE PRINTING TELEGRAPH SYSTEM 2 Sheets-Sheet 2Filed May 25, 1945 INVENTOR. Jon More TTORNEY.

Patented May 24, 1949 PRINTING TELEGRAPH SYSTEM John B. Moore, Brooklyn,N. Y., assigner to Radio Corporation .of America, a corporation ofDelaware Application May 23, 1945, Serial No. 595,303

9 Claims. 1

This invention relates to .printing telegraph systems and apparatus, andmore particularly to such as, use. the five-unit or nre-element BaudotCode- Heretofcre., radio and land line printing telegraph systemsemploying the live-unit '00de have used` either On-Qfl keying, oi aCarrier or plus andY minus (T)4 keying of a direct current for theelements of the code. 'Stated in other words, it has been the custom totransmit either current or no current, or positive and negative directcurrents for the different elements of the five-unit code. The inherentlimitation imposed by only two conditions of signal have limited thepossibilities of printer operation on a channel of specied electricalbandwidth. 'This has resulted in a presently used (conventional)fiveunit printer code which provides a total of only 32 possiblecombinations, and an error-indicating seven-unit code which providesonly 35 possible combinations. These codes both permit of only o,three-bank typewriter keyboard instead of the standard typewriterkeyboard of four banks vor row-s of keys. Experience has shown that thethree-bank keyboard does not satisfactorily meet the needs of thetelegraph industry and the business- World.

The present invention provides a telegraph .ables the printer-equipmentto be at least equivaient to the standard typewriter.

apparatus of the invention employs polarized current relays which have aneutral position in addition to the plus and minus positions. Thesepolarized relays may be ofthe conventional electromechanical type or aspecial design, for example, an electronic equivaient. Where tapetransmission is employed in the invention, `then. the tape perforatorand the tape transmitter each require ten pins, i. e., nve pairs ofpins. The perforator will use ten punch pins to perforate the tape,while the tape transmitter will use the ten pocker-pins for cooperationwith the perforations punched .in the tape.

The two pins of each pair are assigned to each unit .or element of thefive-.unit code, one pin for the plus impulse and the other for theminus impulse. The absence of perforations in the tape at the locationassigned to one pair of pins of the transmitter produces the unmodulatedor neutral condition of signal for that time element or unit.

In the receiving printer of the invention, all code bars are normallyirl the, neutral (middle) position. A selecting impulse moves the 00dehar ,either to the left or to the right from its neutral positionthrough the medium of a suitable magnet System. this receiving printer,vthere are ve different magnet systems vfor the five different units orelements of the rive-unit code. The direction of movement of the magnet,and hence of the code selector bar, is determined by the sign (sense orfrequency) of the received selecting impulse.v Restoration of the codebars to their neutral position is accomplished by a wedge or V-shapedmember driven into correspondingly positioned V-shaped cuts in the codebars. Such restoring action takes place in a manner similar to thatoccurring in the normal sequence of operation in conventional printerapparatus.

The present invention utilizing the principle of three conditions ofsignal in the live-unit code is applicable to either radio or land lineprinting telegraph service in which frequency-shift keying is utilized.

A more detailed description of the invention follows in conjunction withdrawings, wherein:

Fig. l illustrates code charts showing the different combinationspossible with the code of the invention, as applied to a five-unit code;

Fig. 2 illustrates the apparatus of a transmitting station in accordancewith thde invention, suitable for use with my new code;

3 illustrates, by way of example only, one arrangement which the fivepairs of pocker pins in the tape transmitter of Fig. 2 may take forcooperation with the advancing perforated tape;

Fig. 4 illustrates one arrangement of the receiving printer apparatus ofthe invention, capable of receiving the signals transmitted by thetransmitting yapparatus of Fig. 1.

Referring to Fig. Vl in more detail, there are shown four code chartslabeled columns I, II, I II and IV showing a total of eighty dilerentcode combinations possible with the live-unit code of the invention. Thereference numerals l to 5 at the top of each column represent vedifferent units or elements of the code. The plus (-l-) sign representsthe mark signal condition; the minus sign represents the space signalcon 1"ion, while the i sign represents the neutral signal conditi Thus,the il sign indicate the unmcdulated (neutral) carrier duency con -onproduced by an audio tone or radio treo ncy oscillator, while the plusand m si ate the frequencies on both sides of duced by shi ng thefrequency of the oscillan tor to one side or the other in accordancewith the particular sense or sign of the code unit or ment. it shouldnoted that all code combinations contain three selecting elements andtwo non-select 1g elements.

Ii desired, the invention may be utilized with receiver printersequipped with error indicating mechanism io; producing a characteristicindication whenever more or fewer than three selecting impulses arereceived per code combination. Such error indicating mechanism isdescribed in my Reissue Patent No. 22,394, granted November 23, 1943,and in my copending application Serial No. 548,206, filed August 5,1944, now abandoned.

Columns I and II each contain twenty-four different code combinations orcharacters which are the inverse of each other. Columns III and Il! eachcontain sixteen different code combinations or characters which are theinverse of each other. Ii it is desired to avoid the use of inversions(complementary combinations), then the code charts of column I and IIIor II and IV only can be used. It should be noted from an inspection ofthe charts of Fig. 1 that sixty of the eighty possible combinationscontain three conditions of signal, while others contain two conditionsof signal. Obviously, if desired, the code can be set up to use only thesixty code combinations containing the three conditions of signal.

In View of the greater number of code combinations available in the codeof the invention as compared to the conventional live-unit code, it ispossible to transmit a practical maximum of intelligence for a givennumber of time elements per code combination and for a given band widtho1" the communication channel, and to more completely realize the fullpossibilities o frequency shift keying.

Fig. 2 shows a two-channel or diplex trans mitting arrangement forutilizing the rive-unit code in accordance with the invention. Althoughapparatus for two channels are shown, it should be und-fftood that, ifdesired, only one channel vmay be used. Two or more channels arepreerred, however, because they permit the use ol' local unctions in theapparatus, such as tape advance or type-bar operation in one channelduring selection on the other channel.

lt should 'oe understood that the apparatus of Fig. 2 utilizes standardpractice applied to startstop printer telegraph systems, except asmodified in the manner described herein, and for this reason only thosefeatures are described which are essential to an understanding of theoperation of the invention.

Channels A and B each include a ve-unit code tape periorator l@ havingve pairs of punch pins for punching perforations in advancing tape l? inaccordance with the code characters of the signal to be transmitted.Each unit or time element of the five-unit code has one pair of punchpins assigned to it in the tape perforator and these pins are controlledby suitable punch magnets, in turn controlled by the printer keys. lTheperforated tape l2 is fed into an automatic tape-controlled transmitteri4 which is also provideo with nve pairs of pocker pins, one pair foreach unit or time element of the five-unit code. The positions of pockerpins are arranged to cor respond to the positions of the punch pins inthe perforator It in relation to the tape l2. Thus, il the tape l2 isperforated such that all holes are in a straight line transverse to thedirection of movement of the tape, then the pecker pins of tapetransmitter Hl should also be arranged in a straight line transverse tothe moving tape. This is shown in Fig. 3. Alternatively, the holes inthe tape l2 can be arranged in two straight parallel lines extendingtransversely of the direc tion of the moving tape, in which case thefive pairs of pecker pins in the tape-controlled transmitter should alsobe arranged correspondingly in two straight parallel lines of ve pinseach, with the pins of each pair being arranged in dif lines. In thislast case, the tape should be advanced by the sprocket (star wheel)drive two center holes for each code character.

tape-controlled transmitter lil is provided with contacts c, e, f, and ywhich are con- Y; trolled by the tape and these contacts serve tosupp-ly either positive volts direct current, negative 120 volts directcurrent, or no current at all to the leads l, 2, 3, d, and 5 extendingto the similarly designated segments on the distributor it, which areassigned to that particular channel.

Fig. 3 illustrates how the ve pairs of pocker pins of the automatic tapecontrolled transmitter lll are arranged in a single straight linetransverse to the advancing tape I2 when the perorations in the tape aresimilarly positioned. Only one pair ci pecler pins Il, i3 have beenshown in some detail in order to illustrate the manner in which the pinsare pivoted and arranged to close con i tacts e whenever the pins passthrough the periorations in the tape. The pins are permitted to projectthrough the perforations in the tape when the tape is in position for acode signal to be sent out. lf pin ll projects through a perforation,then an obvious circuit is closed to pass positive direct current fromsource +120 volts over lead 3 to the distributor segment 3. Simd ilarly,if pin i3 projects through a perforation, then an obvious circuit isclosed to pass negative direct current from source 120 volts over leadil. If neither pin ll nor i3 projects through. a perforation, then thecircuit through lead 3 is open and no current passes to the distributor`over lead 3. Upon completion of the transmission of a code signal, thepins l l and i3 (and the other pocker pins as well) are withdrawn fromthe tape downwardly under control of a member ll secured to a caro it.The star or ratchet wheel for feeding the perforated tape is not shownsince this feature follows standard practice, but this feed mechanismand the movement of member ll are correlated to the speed of rotation ofthe brush arm on distributor I6, in turn synchronized with thedistributor in the receiver apparatus of Fig. 4.

Distributor ifi is provided with five ses" ments l to 5 for each channelA or B, and these are located on a single circle. There also areprovided such other segmented rings as are required to fulll knownfunctions according to standard practice. Those other rings and segmentson the distributor which do not relate to the invention have not beenshown. The dis- .tributor le is also provided with a solid ring RTbl-usb arm rotates. ifrom the s'haft-'Sbyiinsulation AI.

aneignen together and are secured to a movable armwhich `isv'driven inthe direction 'of the arrowby-a shaft AiS ydriven by Ya v`motor v(--notshown). iBrush 2BR makes `continuous lcontact with ring '-R, whilesbrush 'BR' makes contact iwith the different spaced segments 5| to i5"of -e'ac'h channel as the The brush arm is finsulated 'The speed ofrotation of the `rbrush arm iis i correlated to the operaticnlof theautomatic tape- "controlled 'transmitters fso :that the 'segments .off-the distributorassigned to each channel zare :all I.swept over by thebrush fBR once for each =code #character or 'combination Lof that"channel,

The output from the distributor is taken .off zby vlead iii which isconnected ftc polarized direct current relay i211. The armature .Zl fofrelay 320 :remains in a neutral .position midway vbetween -rcontacts 22yand 24 unless .pulled :over ito engage fone of these contacts or theother.

A positive currentiderivedfrom a particular segment on the distributorand applied to relay '2.'01fr0m lead HI8 4will `cause the armature 12|5to fengageione 'of the contacts,:let us say 22,'while .a negative cur--`rent Vapplied to :relay 123 will -cause armature `2| to engage contact'24. iIn the .absence of currenten lead I3, Vthe `armature '.21 willreturn lto I.its neutral or midway position between both 'con- =tacts.

yPolarized relay `20 vserves'to Ishift .the frequency of an oscillator26 to 'one side or the other of Va -mid frequency. Oscillator 126 .isdesigned to :gen- Acrate fa tone in the audio frequency,frange if thesystem of fthe .invention is .to .be used on land lines, but isd'esignedfto gen'errateradio frequency waves ifithe system of1theiinvention isto beiused .in va radiocsystem having anantenna. Whenvthe relay 2li is unenergized, `the yoscillator 25 genlerategfa carrierfrequency representative "of fthe neutral.signaliconditionfand indicatedby the-il `(zero) `designation-on 'the code V'charts of Fig. y1.

AWhen the relay 2li is energized with a. positive current representativeoi-themark signalcondivtion .andindicatedby'the plus-designation onrtlieIcode'charts of Fig. .1, the frequencyof the oscillator is shiftedin-one-directionadesired amount above (or below) relative totheunmodulated carrier (neutral position). When the L.relay 2D is energizedwith a negative cur-rent representative of ythespace signal conditionandindicated by the minus designation on the code charts of 1, .thefrequency of .the oscillatoris shifted .in the other .direction adesired Vamount below system ofthe invention-utilizes land lines fas atransmission medium between the transmitter vand the receiventhenthesignals on leads 25 Will be a tone in the audio frequency range..I-f,

however, the system ci the invention provides radio service, then thesignals on leads will comprise radio 'frequency waves. In vthis'la'stcase, leads 'Z5-can be "fed by a suitable'antenrra circuit. Amplier 2lfeeds'fasuitable discrim- -inator circuit whose output, inthe 'form ofdirect cur-rent, controls Y"a direct-'current :polarized .fre-

The frequency shifts of the 5 @lay Discriminat'or y281servesto convertthe `received2'frequency-shift-keyed. signals of an Aa1- lternatingcurrent character to direct current,

and suppliesathe winding of relay 29 with a posi- A5 tivedirect-'currentvoltage or a negative directcurrent voltage, or novoltage, depending upon vthe characteristics of the'time elements of the`received 'code combinations constituting the veuunitcode.

Polarized vrelay .29 has its armature 30 nor- -mallymaintainedin aposition midway between .its'two contacts. The energization of therelaywinding'by a positive direct current ywill cause 1the 4armature to movein one direction, while the lapplication of a negative direct current tothe winding will cause the armature to move in an opposite direction. Inthe absence of current applied tov'therelay winding, the armature willrefmain in or return to a neutral position midway 20 v:between thecontacts 3l and 32, as shown.

:Armature 30 is connected to the positive terminal :ofJabattery 33 whosenegative terminal is connected'infcommcn, via lead to the polar- .vizedvmagnets ci each nyc-unit code receiver printer.

The receiving apparatus is also provided with :'ardistributor 'Mlhavingltwo solid rings C and D and two segmented rings E and F. Each ofthe lsegmented rings 'E and F are provided Iwith ten @equal lengthspaced segments, there being five segments provided for each of thechannels A :Land B. The iive upper segments on each of the :rings E andF are assigned to channel A, while 7t-he 'iive lower segments on thesesame rings are rassigned to channel B. Solid ring C is connected `'toContact 3l of-polarized relay 29, while solid yring connectedv tocontact 32 of polarized relay 29. 'Suitable brush carrying arms M and :Nvindividually'connect solid rings C and D to `qu segmented rings E andF, respectively. These -arms areonly shown diagrammatically and aredriven 'in .the direction `of the arc-shaped arrow :by lmeansof arotatable shaft, not shown, to thereby Yelectrically connect the rings Cand D sequentially with the individual segments of therings -E^ and F.

The Viive upper-spaced segments designated I 'fto "of rings Eand Fconnected to the iive different codefselecter-bar control magnets 36v'of the receiver printer of channel A. while the five lower spacedvsegments l to 5 of rings and F "are connected to the riive differentcode-selectorybarcontrol magnets of the receiver printer of channel B.The same numbered segments of the *rings E and-F for the same channelare connected to diiferent windings of the same code-selectorbar magnetin its associated receiver printer, as shown.

Oniy c. been shown as part of the receiv p r, but it should. beunderstood "that 'there are other such magnets and their individuallyassociated code-selector-bars in the .receiver printer. Each receiverprinter is provided with individual magnets for the five time elementsor units of the five-unit code. Since the duplication of elementsfollows standard practice, it is not deemed necessary to show more thanone magnet system. Each polarized magnet '3.6 is ...provided with twowindings 3'! and 38 to .control the movement of its code selector bar'39 in either of .two directions, depending upon which .magnet .winding.is energized. The energize-tion alof magnet winding 3l will pull ycodeselector bar .(3:9to the .-left, .while the energization of magnet 7winding 38 will pull code selector bar 39 to the right. When there is nocurrent applied to either magnet Winding, the code selector bar 39 willremain in its normal or reset position.

During the reception or" a code signal combinavIiirgixe-ererated member@3' which functions to re-set all code-selector bars 39 to their neutralor normal position after each selection has been made and a letterprinted in the receiver.

The speed of the distributor i0 is synchronized with, and has the samespeed as, distributor I5 at the transmitting end of the system. Thus,the time duration oi a brush arm in passing over a segment of thedistributor I is correlated to the time interval of one of the units ofthe ve unit code.

At this time it should be noted that apparatus 2T, 2B, 29, 33 and li@are common to the receiver printers of both channels.

For the purpose of exposition, let it be assumed that the brush arms ofdistributor MI are on the number i segments, as shown, and that thesense of the signal character received at that particular moment is suchas to cause polarized relay 29 to close contacts 3l! and 32. A circuitwill then be completed over a path from the positive terminal oi battery33, over contacts 3i! and 32 of relay 29, solid ring D, brush arm N,segment i of segmented ring F, through Winding 38 of polarized magnet 36and lead 3G back to the negative terminal of battery 33. This closedcircuit Will energize winding 3S and cause the magnet 36 t0 pull codeselector bar 39 to the right. If, however, it is assumed that the senseof the received signal is such as to operate relay 29 to close contactsd and 3i at the particular moment When the distributor itil is in theposition illustrated, then a circuit will be completed over a pathincluding solid ring C, brush arm M and Winding 3'! of magnet to causethe code selector bar 39 to be pulled to the left. The continuedreceiptv of signals While the distributor brush arms are rotating willcause the polarized relay Z9 to assume different contact positions inaccordance with sense of the signals and hence set up the controlmagnets in the receiver printers to print the desired letter.

The principles of the invention are equally applicable to a four-unitprinter code, although it should be understood that by reducing thetotal number oi time elements per character to four, in place of ve, itis possible to obtain thirty-two combinations and to transmituve-fourths times as many Words per minute over existing channelscompared to the conventional five-unit on-oi code, at the same keyingspeeds in bands. This five-fourths increase in Words per minute requiresno increase in channel width.

What is claimed is:

1. A printing telegraph system for transmitting intelligence by means ofan m-unit code, the irldividual elements of which comprise one of threepredetermined conditions of signal, comprising an m-unit-code tapeperforated in accordance with the code combinations to be transmitted,an

`munitcode automatic tape-controlled transmitter fed with said tape andhaving m pairs of pins for cooperation with the perforations in saidtape, the pins in said tape-controlled transmitter being arranged insimilar relation to the perforations in said tape, said tape-controlledtransmitter having m pairs of contacts controlled by its m pairs ofpins, a distributor having m different connections for operativeassociation With the m different pairs of contacts of saidtape-controlled transmitter, and means in said tapecontrolledtransmitter for supplying each connection with a positive vol-tage Whenone contact of its associated pair oi contacts is closed, With anegative voltage when the other contact of its associated pair ofcontacts is closed, and with no voltage when neither contact of itsassociated pair is closed, an oscillator, means in circuit with saidoscillator and under control of the output from said distributor forchanging its frequency of operation to a second frequency when apositive voltage is supplied by said distributor and to a thirdfrequency when a negative voltage is supplied by said distributor, meansfor transmitting signal Waves of said three different frequencies,receiving apparatus including frequency responsive means for convertingthe received signal waves to three conditions of signal constitutingpositive, negative and no current, a receiving distributor having mpairs of contacts coupled to said converting means, and a printer havingm selector bars and associated therewith m polarized code-selector-barmagnets correspending to the m units of the code coupled to saidreceiving distributor, said magnets controlling diiierent code selectorbars to cause said bars to assume any one of `three different positionscorresponding to said positive, negative, and no current conditions ofsignal.

2. A printing telegraph system for transmitting intelligence by means oia Xed-unit-code, the individual elements oi which comprise one of threepredetermined conditions of signal, comprising a tap perforated inaccordance with the code combination to be transmitted, the perforationpattern of said tape being arranged in pairs of perforations, one ofsaid perforations representing one of said conditions of signal, theother of said perforations representing another of said conditions ofsignal and the absence of said perforations representing a furthercondition of signal, a tape-controlled transmitter fed With said tapeand having pairs of pins 4for cooperation with the perforations in saidtape, the pins in .said transmitter being arranged in relation to thepairs of perforations in said tape, said transmitter having pairs ofcontacts controlled by each of its pairs of pins, a distributor havingdifferent connections for operative association with the diierent pairsof contacts of said tape-controlled transmitter, an oscillationgenerator having a frequency determining circuit, an output circuit forsaid generator, a polarized relay havof signal frequency to said outputcircuit, transmission means coupled to said output circuit, frequencydetecting means coupled to said transmission means 'for developing onecurrent corresponding to one condition of signal frequency, a secondcurrent corresponding to another condition of signal frequency, and nocurrent corresponding to a 'further condition of signal frequency,polarized relay means coupling said detecting means to a printer havingpolarized codeselector-bar magnets corresponding to the units of saidcode, said magnets controlling different code-selector bars in saidprinter to cause said bars to assume one of three different positionscorresponding to said three conditions of signal, each of saidcode-selector bars having a V-shaped slot therein, and a V-shapedsolenoid-operated mechanism for re-setting said bars to normal aftereach selection and printing operation.

3. Printing telegraph transmitting apparatus for transmittingintelligence from a transmitting tape having ive-unit-code perforationsin accordance with the code combination to be transmitted, comprising a:dve-unit-code automatic tape-controlled transmitter fed with said. tapeand having ve pairs of pins for cooperation with the perforations insaid tape, the pins in said tape-controlled transmitter being arrangedin similar relation to the perforations in said tape, saidtape-controlled transmitter having ive pairs of contacts controlled byits five pairs of pins, a distributor having five different connectionsfor operative association with the five dierent pairs of contacts ofsaid tape-controlled transmitter, and means in said tape-controlledtransmitter for supplying each connection with a positive voltage whenone contact of its associated pair of contacts is closed, with anegative voltage when the other contact of its associated pair oicontacts is closed, and With no voltage when neither contact of itsassociated pair is closed.

4. Printing telegraph transmitting apparatus for transmittingintelligence from a transmitting tape having five-unit-code perforationsin accordance with the code combination to be transmitted, comprising afive-unit code automatic tape-controlled transmitter fed with said tapeand having five pairs of pins for cooperation with the perforations insaid tape, the pins in said tape-controlled transmitter being arrangedin similar relation to the perforations in said tape, saidtape-controlled transmitter having ve pairs of contacts controlled byits ve pairs of pins, a distributor having five different connectionsfor operative association with the live different pairs of contacts ofsaid tape-controlled transmitter, an oscillator, and means in circuitwith said oscillator and under control of the output from saiddistributor for changing its frequency of operation to a secondfrequency when a positive voltage is supplied by said distributor and toa third frequency when a negative voltage is supplied by saiddistributor.

5. Printing telegraph transmitting apparatus for transmittingintelligence from a transmitting tape having five-unit-code perforationsin accordance With the code combination to be transmitted, comprising ave-unit-code automatic tape-controlled transmitter fed with said tapeand having five pairs of pins for cooperation with the perforations insaid tape, the pins in said tape-controlled transmitter being arrangedin similar relation to the perforations in said tape, saidtape-controlled transmitter having iive pairs of contacts controlled byits five pairs of pins, a

lili

distributor having iive different connections ior operative associationwith the five diferent pairs of contacts of said tape-controlledtransmitter, an electron discharge device oscillation generator having afrequency determining circuit, an output circuit for said oscillator, apolarized relay having a Winding controlled by the output from saiddistributor and -a pair of contacts connected to different points onsaid frequency determining circuit, said poiarized relay beingresponsive to 'positive voltage from said distributor to cause saidoscillator to change its frequency in one direction from its normalcarrier frequency and being responsive to a negative voltage from saiddistributor to cause said oscillator to change its frequency in anopposite direction from its normal carrier frequency, whereby saidoscillator supplies three conditions of signal to said output circuit.

6. In a receiving station for receiving from a transmitting stationsending ve-unit-code combinations having three conditions oi signal, .areceiver printer having five polarized code-selector-bar magnetscorresponding to the five units of the code, a distributor havingdiierent segments connected to different ones of said magnets,individual code-selector bars for said mag-- nets, said magnetscontrolling diierent codeselector bars in said receiver printer to causesaid bars to assume any one of three dierent positions corresponding tosaid three conditions or signal.

7. In a iive-unit-code signaling system wherein the code combinationsmake use of three conditions of signal, a receiver printer having fivepolarized code-selector-bar magnets corresponding to the rive units oithe code, a distributor having dierent segments connected to diiierentones of said magnets, individual code-selector bars for said magnets,said magnets controlling three conditions of signal.

8. In a iive-unit-code signaling system wherein the code combinationsmake use of three conditions of signal, a receiver printer having fivepolarized code-selector-bar magnets corresponding to the iive units ofthe code, a distributor having different segments connected to differentones of said magnets, individual code-selector bars for said magnets,said magnets controlling different code-selector bars in said receiverprinter to cause said bars to assume any one of three dierent positionscorresponding to said three conditions of signal, each of saidcodeseiector having a V-shaped slot therein, and a il-shapedsolenoid-operated mechanism for resetting said bars to normal after eachselection and printing operation.

9. In a telegraph system having printing telegraph transmittingapparatus comprising a fiveunit-code transmitter supplying threeconditions oi signal for diierent code combinations and means forconverting said three conditions of signal to Waves of three differentfrequencies, receiving apparatus including means for converting receivedcode combinations to three conditions of signal constituting positive,negative and no current, and a receiver printer having five polarizedcode-selector-bar magnets corresponding to the five units of the code, adistributor having diiferent segments connected to diierent ones of saidmagnets, individual code-selector l1 bars for said magnets, said magnetscontrolling different code selector bars to cause said bars to assumeany one of three different positions corresponding to said positive,negative, and no current conditions of signal and pull bars selectivelypositioned in coded slots in said code selector bars dependent on theposition thereof.

JOHN B. MOORE.

REFERENCES CITED The following references are of record in the file ofthis patent:

Number 12 UNITED STATES PATENTS Name Date Tevis June 7, 1932 BeverageDec. 24, 1935 Beverage Feb. 9, 1937 Masson Oct. 5, 1937 Fitch Apr. 2,1940 Hanley Feb. 25, 1941 Noxon Nov. 25,l 1941 Bellescize May 26, 1942Reiber Nov. 3, 1942 Hartley Dec. 30, 1947

